A Max-Plus Model of Asynchronous Cellular Automata

This paper presents a new framework for asynchrony. This has its origins in our attempts to better harness the internal decision making process of cellular automata (CA). Thus, we show that a max-plus algebraic model of asynchrony arises naturally from the CA requirement that a cell receives the state of each neighbour before updating. The significant result is the existence of a bijective mapping between the asynchronous system and the synchronous system classically used to update cellular automata. Consequently, although the CA outputs look qualitatively different, when surveyed on "contours" of real time, the asynchronous CA replicates the synchronous CA. Moreover, this type of asynchrony is simple - it is characterised by the underlying network structure of the cells, and long-term behaviour is deterministic and periodic due to the linearity of max-plus algebra. The findings lead us to proffer max-plus algebra as: (i) a more accurate and efficient underlying timing mechanism for models of patterns seen in nature, and (ii) a foundation for promising extensions and applications.Comment: in Complex Systems (Complex Systems Publications Inc), Volume 23, Issue 4, 201

Recreating Daily life in Pompeii

[EN] We propose an integrated Mixed Reality methodology for recreating ancient daily life that features realistic simulations of animated virtual human actors (clothes, body, skin, face) who augment real environments and re-enact staged storytelling dramas. We aim to go further from traditional concepts of static cultural artifacts or rigid geometrical and 2D textual augmentations and allow for 3D, interactive, augmented historical character-based event representations in a mobile and wearable setup. This is the main contribution of the described work as well as the proposed extensions to AR Enabling technologies: a VR/AR character simulation kernel framework with real-time, clothed virtual humans that are dynamically superimposed on live camera input, animated and acting based on a predefined, historically correct scenario. We demonstrate such a real-time case study on the actual site of ancient Pompeii.The work presented has been supported by the Swiss Federal Office for Education and Science and the EU IST programme, in frame of the EU IST LIFEPLUS 34545 and EU ICT INTERMEDIA 38417 projects.Magnenat-Thalmann, N.; Papagiannakis, G. (2010). Recreating Daily life in Pompeii. Virtual Archaeology Review. 1(2):19-23. https://doi.org/10.4995/var.2010.4679OJS192312P. MILGRAM, F. KISHINO, (1994) "A Taxonomy of Mixed Reality Visual Displays", IEICE Trans. Information Systems, vol. E77-D, no. 12, pp. 1321-1329R. AZUMA, Y. BAILLOT, R. BEHRINGER, S. FEINER, S. JULIER, B. MACINTYRE, (2001) "Recent Advances in Augmented Reality", IEEE Computer Graphics and Applications, November/December http://dx.doi.org/10.1109/38.963459D. STRICKER, P. DÄHNE, F. SEIBERT, I. CHRISTOU, L. ALMEIDA, N. IOANNIDIS, (2001) "Design and Development Issues for ARCHEOGUIDE: An Augmented Reality-based Cultural Heritage On-site Guide", EuroImage ICAV 3D Conference in Augmented Virtual Environments and Three-dimensional Imaging, Mykonos, Greece, 30 May-01 JuneW. WOHLGEMUTH, G. TRIEBFÜRST, (2000)"ARVIKA: augmented reality for development, production and service", DARE 2000 on Designing augmented reality environments, Elsinore, Denmark http://dx.doi.org/10.1145/354666.354688H. TAMURA, H. YAMAMOTO, A. KATAYAMA, (2001) "Mixed reality: Future dreams seen at the border between real and virtual worlds", Computer Graphics and Applications, vol.21, no.6, pp.64-70 http://dx.doi.org/10.1109/38.963462M. PONDER, G. PAPAGIANNAKIS, T. MOLET, N. MAGNENAT-THALMANN, D. THALMANN, (2003) "VHD++ Development Framework: Towards Extendible, Component Based VR/AR Simulation Engine Featuring Advanced Virtual Character Technologies", IEEE Computer Society Press, CGI Proceedings, pp. 96-104 http://dx.doi.org/10.1109/cgi.2003.1214453Archaeological Superintendence of Pompeii (2009), http://www.pompeiisites.orgG. PAPAGIANNAKIS, S. SCHERTENLEIB, B. O'KENNEDY , M. POIZAT, N.MAGNENAT-THALMANN, A. STODDART, D.THALMANN, (2005) "Mixing Virtual and Real scenes in the site of ancient Pompeii",Journal of CAVW, p 11-24, Volume 16, Issue 1, John Wiley and Sons Ltd, FebruaryEGGES, A., PAPAGIANNAKIS, G., MAGNENAT-THALMANN, N., (2007) "Presence and Interaction in Mixed Reality", The Visual Computer, Springer-Verlag Volume 23, Number 5, MaySEO H., MAGNENAT-THALMANN N. (2003), An Automatic Modeling of Human Bodies from Sizing Parameters. In ACM SIGGRAPH, Symposium on Interactive 3D Graphics, pp19-26, pp234. http://dx.doi.org/10.1145/641480.641487VOLINO P., MAGNENAT-THALMANN N. (2006), Resolving Surface Collisions through Intersection Contour Minimization. In ACM Transactions on Graphics (Siggraph 2006 proceedings), 25(3), pp 1154-1159. http://dx.doi.org/10.1145/1179352.1142007http://dx.doi.org/10.1145/1141911.1142007PAPAGIANNAKIS, G., SINGH, G., MAGNENAT-THALMANN, N., (2008) "A survey of mobile and wireless technologies for augmented reality systems", Journal of Computer Animation and Virtual Worlds, John Wiley and Sons Ltd, 19, 1, pp. 3-22, February http://dx.doi.org/10.1002/cav.22

Gibbs entropy and irreversible thermodynamics

Recently a number of approaches has been developed to connect the microscopic dynamics of particle systems to the macroscopic properties of systems in nonequilibrium stationary states, via the theory of dynamical systems. This way a direct connection between dynamics and Irreversible Thermodynamics has been claimed to have been found. However, the main quantity used in these studies is a (coarse-grained) Gibbs entropy, which to us does not seem suitable, in its present form, to characterize nonequilibrium states. Various simplified models have also been devised to give explicit examples of how the coarse-grained approach may succeed in giving a full description of the Irreversible Thermodynamics. We analyze some of these models pointing out a number of difficulties which, in our opinion, need to be overcome in order to establish a physically relevant connection between these models and Irreversible Thermodynamics.Comment: 19 pages, 4 eps figures, LaTeX2

A Survey on Continuous Time Computations

We provide an overview of theories of continuous time computation. These theories allow us to understand both the hardness of questions related to continuous time dynamical systems and the computational power of continuous time analog models. We survey the existing models, summarizing results, and point to relevant references in the literature

BDGS: A Scalable Big Data Generator Suite in Big Data Benchmarking

Data generation is a key issue in big data benchmarking that aims to generate application-specific data sets to meet the 4V requirements of big data. Specifically, big data generators need to generate scalable data (Volume) of different types (Variety) under controllable generation rates (Velocity) while keeping the important characteristics of raw data (Veracity). This gives rise to various new challenges about how we design generators efficiently and successfully. To date, most existing techniques can only generate limited types of data and support specific big data systems such as Hadoop. Hence we develop a tool, called Big Data Generator Suite (BDGS), to efficiently generate scalable big data while employing data models derived from real data to preserve data veracity. The effectiveness of BDGS is demonstrated by developing six data generators covering three representative data types (structured, semi-structured and unstructured) and three data sources (text, graph, and table data)

Robust moving horizon H∞ control of discrete time-delayed systems with interval time-varying delays

In this study, design of a delay-dependent type moving horizon state-feedback control (MHHC) is considered for a class of linear discrete-time system subject to time-varying state delays, norm-bounded uncertainties, and disturbances with bounded energies. The closed-loop robust stability and robust performance problems are considered to overcome the instability and poor disturbance rejection performance due to the existence of parametric uncertainties and time-delay appeared in the system dynamics. Utilizing a discrete-time Lyapunov-Krasovskii functional, some delay-dependent linear matrix inequality (LMI) based conditions are provided. It is shown that if one can find a feasible solution set for these LMI conditions iteratively at each step of run-time, then we can construct a control law which guarantees the closed-loop asymptotic stability, maximum disturbance rejection performance, and closed-loop dissipativity in view of the actuator limitations. Two numerical examples with simulations on a nominal and uncertain discrete-time, time-delayed systems, are presented at the end, in order to demonstrate the efficiency of the proposed method